The HTC G1. A white plastic slider phone with a physical QWERTY keyboard and a trackball for navigation. Back, home and menu buttons that we've grown to love (or hate) sit under a relatively small touchscreen display. It's 2008. It's the first commercially available phone to ever run Android.

One billion activations and five years later, Android is massively popular, and is virtually unrecognisable from the days when it would cower under the iPhone and Microsoft's measly attempts involving Windows Mobile 6. Android 4.4 KitKat, the next major version, now sits on the horizon, and we wait for greatly-anticipated app redesigns and an accompanying new Nexus phone.

While the G1 – with a 320x480 display, 528 MHz processor and 192 MB of RAM – was the first commercially available Android phone, it's worth noting that the software was in development for some time prior to this announcement. Originally planned to be software for a digital camera, Android was written over a span of five years, notably after Google acquired the company in 2005.

Nevertheless, the issue of fragmentation has remained: Less than 40 percent of phones run Jelly Bean, and a whole 30 percent are still running Gingerbread, a 3-year-old version. In comparison, iOS 7 is currently installed on 58 percent of Apple devices, less than a week after launch. In addition, skins such as Samsung's TouchWiz have arguably damaged Android's reputation, as they remove much of the design initiative that Google have spent so long working on.

But remember: Android is big and successful. In its stock form, it is a fantastic mobile OS, and we cannot wait to see what Google have in store in the future.